东方红林业局ＭＭＤＳ系统始建于１９９５年４月，于当年７月前端调试安装完成。运行至今，前端出现过多种故障，现选出几例典型故障，介绍当时分析思路及维修成败得失。１故障现象：在所有用户电视机上，宽带发射机发射的第一个台的信号与其它信号相比有细小噪点。分析：... Dongfanghong Forestry Bureau MMDS system was founded in April 1995, in July that year front-end debugging installation is completed. Running so far, there are many front-end failure, is now selected a few typical faults, introduced the analysis of ideas and maintenance success or failure. 1 Symptom: On all subscriber televisions, the signal from the first station transmitted by the wideband transmitter has fine noise compared to the other signals. analysis:...